<template>
  <view>
    <!-- 使用自定义的搜索组件 -->
    <!-- <my-search :bgColor="'#000000'" :radius="5"></my-search> -->
    <my-search @click="gotoSearch"></my-search>
    <view class="scroll-view-container">
      <!-- 左侧滑动区域 -->
      <scroll-view class="left-scroll-view" scroll-y="true" :style="{height:wh+'px'}">
        <block v-for="(item,i) in cateList" :key="i">
          <view :class="['left-scroll-view-item', i===active?'active':'']" @click="activeChanged(i)">{{item.cat_name}}
          </view>
        </block>
      </scroll-view>
      <!-- 右侧滑动区域 -->
      <scroll-view class="right-scroll-view" scroll-y="true" :style="{height:wh+'px'}" :scroll-top="scrollTop">
        <!-- 渲染二级分类的标题 -->
        <view class="cate-lv2" v-for="(item2,i2) in cateLevel2" :key="i2">
          <view class="cate-lv2-title">
            /{{item2.cat_name}}/
          </view>
          <!-- 从二级分类中取出三级分类并渲染 -->
          <view class="cate-lv3-list" >
            <!-- 三级分类的item项 -->
            <view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
              <!-- 三级分类的img -->
              <image :src="item3.cat_icon"></image>
              <!-- 三级分类的标题 -->
              <text>{{item3.cat_name}}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
  import badgeMix from '@/mixins/tabbar-badge.js';
  
  export default {
    mixins:[badgeMix],
    data() {
      return {
        // 动态获取屏幕可用高度
        wh: 0,
        // 存放分类列表数据
        cateList: [],
        // 激活项的索引
        active: 0,
        // 存放二级分类数据
        cateLevel2: [],
        // 滚动条距离顶部的距离
        scrollTop:0
      };
    },
    onLoad() {
      // 获取设备信息
      const sysInfo = uni.getSystemInfoSync();
      // 可用高度 = 屏幕高度 - navigationBar高度 - tabBar高度 - 自定义组件高度
      this.wh = sysInfo.windowHeight - 50;
      // 获取分类列表数据
      this.getCateList();
    },
    methods: {
      async getCateList() {
        // 发起请求
        const {
          data: res
        } = await uni.$http.get('api/public/v1/categories');
        // 判断是否获取失败
        if (res.meta.status !== 200) {
          return uni.$showMsg()
        }
        // 转存数据
        this.cateList = res.message;
        // 为二级分类数据赋值
        this.cateLevel2 = res.message[0].children;
      },
      activeChanged(index) {
        // 选中项的索引即为激活项的索引
        this.active = index;
        // 重新为二级分类数据赋值
        this.cateLevel2 = this.cateList[index].children;
        // 切换滚动条高度的值
        this.scrollTop = this.scrollTop?0:1;
      },
      gotoGoodsList(item3){
        uni.navigateTo({
          url:'../../subpkg/goods_list/goods_list?cid=' + item3.cat_id
        })
      },
      gotoSearch(){
        uni.navigateTo({
          url:'../../subpkg/search/search'
        })
      }
    }
  }
</script>

<style lang="scss">
  .scroll-view-container {
    display: flex;
  }

  .left-scroll-view {
    width: 120px;
  }

  .left-scroll-view-item {
    background-color: #F7F7F7;
    line-height: 60px;
    font-size: 12px;
    text-align: center;

    &.active {
      background-color: #ffffff;
      position: relative;

      &::before {
        content: '';
        width: 3px;
        height: 30px;
        position: absolute;
        background-color: #c00000;
        display: block;
        top: 50%;
        left: 0;
        transform: translateY(-50%);
      }
    }
  }

  .cate-lv2-title {
    font-size: 12px;
    font-weight: bold;
    text-align: center;
    padding: 15px 0;
  }

  .cate-lv3-list {
    display: flex;
    flex-wrap: wrap;

    .cate-lv3-item {
      width: 33.3%;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      margin-bottom: 10px;

      image {
        width: 60px;
        height: 60px;
      }

      text {
        font-size: 12px;
      }
    }
  }
</style>
